Malignant mesothelioma following thoracic radiotherapy for lung cancer.

As the number of long-term cancer survivors increases, secondary malignancies are becoming a greater clinical issue. Although some of these malignancies may be related to common environmental exposures, a significant number are considered to be therapy-related. Pleural malignant mesothelioma is a neoplasm that may be related to asbestos exposure or radiation exposure. Previous reports of pleural mesothelioma as a second malignancy have tended to follow radiotherapy for extra-thoracic malignancies such as Hodgkin's disease, breast cancer and Wilms' tumor. We report the case of a 66-year-old woman with no prior asbestos exposure who developed pleural mesothelioma 17 years after pneumonectomy and adjuvant radiation therapy for non-small cell lung cancer. Opacification of the lung field from prior therapy made determination of the diagnosis more challenging. Secondary malignancies such as mesothelioma should be considered in patients who develop unexplained symptoms even long after treatment of a primary tumor.